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6902M 6hp driveshaft roll pin

N

nytebyte

Regular Contributor
I have 2 6902M Evinrude motors. I picked one up for parts but the motor is to good so I am doing what needs to be done to make it another good one. I pulled the lower unit and found that the roll pin is missing on the driveshaft. What is the purpose of it? Should I replace it? I replaced the water pump in the other motor and I know it lines up the shaft in the exhaust housing but other than that does it serve any purpose? Thanks for any info on it. Jim
 
That pin is very important.-----It drives / rotates the mechanical seal assembly found under the power head.-----Sounds like the powerhead now needs to be removed to inspect / properly assemble that seal.----It at least needs a new gasket and o-ring in there.
 
Thanks for that info. I removed the powerhead this afternoon. All looks good in there now. Parts that I need to replace are the pan under the powerhead and exhaust housing. It was droped and they were damaged beyond repair but I did a compression and spark check and all was good so decided to try and find parts and ebay came threw. Ill replace the roll pin, gasket, and o-ring. I am thinking the local hardware store should have a roll pin for it. $7.00 seems a bit high for that on parts sites!
 
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The pin shears due to the person working on the engine NOT knowing about the pin in the first place. Trying to drop the lower unit with the pin NOT aligned with a slot up near the powerhead, it would refuse to drop.... one would need to have the lower unit in gear and turn the propeller in order to align the pin with the slot to remove the lower unit OR to re-install it. <-- Keep that in mind.

When the pin (part #303261) shears, none of the seal components can slide out of place as they are still on the driveshaft... and when the driveshaft is withdrawn, the spring tension normally keeps all of the seal components where they belong... so it's just a matter of installing the new pin, then remembering to turn the prop (in gear) to align the pin with its slot.
 
My good 6 hp had the pin and i just reused after I installed the waterpump. This motor I was suprised at the fact that the lower unit just dropped after disconecting the shift rod as the other motor I had to turn the prop to line everything up. The pin was still in it but both ends were broke off.
 
nytebyte said:
My good 6 hp had the pin and i just reused after I installed the waterpump. This motor I was suprised at the fact that the lower unit just dropped after disconecting the shift rod as the other motor I had to turn the prop to line everything up. The pin was still in it but both ends were broke off.
Click to expand...

And you reused a worthless broken sheared off pin??
 
LOL No I have 2 of the 6 hp motors. The one I am working on was bought for a parts motor The other motor had nothing wrong with it but I replaced the water pump as part of my maintanance on it and reused the good shear pin that was on it. The broken shear pin was on my parts motor that I decided was worthy of bringing back to life. That one will get a new shear pin when it goes back together.
 
That pin is a 19 cent item.--------But when you are buying it as a spare part from a big organization they want $6.81 for shipping and handling.----They do not make a lot of money selling that one little item.
 
I wish thats all it was. On this site it lists for $7.00 plus shipping. My local dealer will probably only want 9.99 for it.
 
The roll pin was missing on my new Johson 6hp 1977. I purchase a new pin by internet.
When in place the roll pin will spin with the driveshatf. Can you explain me how it does not tear or cratch other parts of the seal. No oil or grease in this area.

Normand
Québec
 
Fact-----This pin puts pressure on a spring and drives a mechanical seal !!----It helps seal the lower crankcase.-----Keeps water out of the engine.------I suggest you remove the powerhead to look at and inspect this mechanical seal.-----It needs a new o-ring and gasket.-----This seal is not a rubber lipped seal that you might be more familiar with.----All elegantly simple stuff to me.-----Own about a dozen or more of these motors.
 
Good news I think!
With a flashlight this morning I have been able to see the slot for the pin, the botton cup sitting the spring and to operate the spring.
Taking off the power head is over my mecanic capacity for now (undo the carb, the starter and plus...)
On receiving the new roll pin I will put it in place (adding grease on it)and reload the lower unit.
By slowly turning the flyweel I will be able to feel and ear if everything look and sound normal.

Normand
Québec
 
The opportunity to learn is here today.-------Remove choke pull., remove slow speed needle.-----Remove starter handle.-----Then just 7 screws and a hose to remove the powerhead.-----Nothing to it.
 
And don't let the starter handle scare you. No need to let the starter rewind. Simply tie a knot in the rope so it can't rewind.
 
Thanks to all the contributors.
Appreciate and fun to have access to experience persons who are generously sharing their knowledge.

Normand
Québec
 
These guys are the best. That old spring loaded crankshaft seal is goofy to some, but truly ingenious. I really believe engineering has deteriorated over the years. This design is virtually bulletproof and uses simple materials like leather. The belt I'm wearing now is 15 years old....carries a supertool, Buck knife, cell phone, tape measure.....trust it and know it will last another 15 years. Hi Joe, happy new year, my friend.

PS. Parts for these are available at Tim's Outboard in Hackensack MN....218 682 2331..…Theresa, Mike and Dan......55 years, family business....beautiful Minnesota freshwater parts.
 
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Really? I'm gonna go look at one now to make sure....maybe I'm thinking the older ones.
Okay...so what fits on top of this washer?
Here is the beautiful carbon section with o-ring....spring below.
Sorry, can't find that leather washer....place is a nightmare....if I get Alzheimer's I'm really screwed.
 

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That part is the stator ( does not rotate ) for the mechanical seal.------A cork gasket fits on that stator , called a washer as well.----Older stators were bronze.-----Newer ones were stainless.
 
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Thanks, I have the stainless stator around here. Imagine in all these years, I always thought that flat gasket was leather.... probably would work just as well, that must be some awesome cork. These seals are engineered to last almost forever. Crap today is like garbage....how about those new 2019 Mercs here on the Forum..?...40 total hours and already seals recalled and replaced with one new powerhead besides....still oil on the water??? Just think of all the quality to be had for only 20 thousand bucks, eh? Go ahead click here and read. I think you, Racer, and also Chris, handled the thread. The guy, OP, is going to try it again today, he said.

http://www.marineengine.com/boat-fo...019-Mercury-Verado-V8-oil-leak-and-fuel-sheen

Nothing like good holsum entertainment, and all for free!

Just let me alone with my old 5 1/2 and the 14' Lone Star up here in the Ontario wilderness....I'll be happy for a long, long time.
 
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